JP2024022631A - Isolation method - Google Patents

Abstract

To provide a method for isolating a fluorocarbon having one carbon atom.SOLUTION: A fluorocarbon isolation method according to the present disclosure comprises isolating a fluorocarbon having one carbon atom from a mixture containing the fluorocarbon having one carbon atom and the fluorocarbon having equal to or more two carbon atoms. The isolation of fluorocarbon having one carbon atom is conducted by bringing the mixture into contact with an absorbent.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a separation method.

As a method for separating fluorocarbons, a method of distilling a mixture of fluorocarbons is known. Patent Document 1 discloses that a mixture containing 2,3,3,3-tetrafluoropropene and hexafluoropropene and an extraction solvent are mixed to obtain an extraction mixture, and then the extraction mixture is distilled. It is described that a distillate based on hexafluoropropene and a bottoms containing 2,3,3,3-tetrafluoropropene are obtained.

Japanese Patent Application Publication No. 2018-002602

In the distillation method as described in Patent Document 1, it is difficult to separate compounds with similar boiling points or azeotropic compounds, and when separating fluorocarbons having 1 carbon number, there may be problems such as insufficient separation. I found it.

An object of the present disclosure is to provide a method for separating fluorocarbons having one carbon number.

The present disclosure includes the following aspects.
[1]
Separating a fluorocarbon having a carbon number of 1 from a mixture containing a fluorocarbon having a carbon number of 1 and a fluorocarbon having a carbon number of 2 or more,
A method for separating fluorocarbons, wherein the separation of the fluorocarbon having 1 carbon number is carried out by bringing the mixture into contact with an adsorbent.
[2]
The separation method according to [1], wherein the fluorocarbon having 1 carbon number is at least one selected from the group consisting of difluoromethane and difluorochloromethane.
[3]
The separation method according to [1] or [2], wherein the fluorocarbon having 2 or more carbon atoms includes a fluorocarbon having 2 to 3 carbon atoms.
[4]
The separation method according to any one of [1] to [3], wherein the adsorbent includes a porous body, and the effective pore diameter of the porous body is 0.46 nm or less.
[5]
The separation method according to [4], wherein the porous body includes a metal-organic structure.
[6]
The metal-organic framework contains a metal ion and one or more organic ligands,
The separation method according to [5], wherein the organic ligand contains two or more groups in one molecule that can coordinately bond to the metal ion.
[7]
The separation method according to [6], wherein the metal ion contains zinc, and the organic ligand contains oxalic acid and 1,2,4-triazole.
[8]
The separation method according to any one of [4] to [7], wherein the adsorbent further contains a resin.
[9]
The separation method according to any one of [1] to [8], wherein the adsorbent is in the form of powder, granules, flakes, or pellets.
[10]
The separation method according to any one of [1] to [9], further comprising refining the separated fluorocarbon having 1 carbon.
[11]
including a metal-organic framework and a fluorocarbon having 1 carbon number,
The metal-organic framework contains a metal ion and one or more organic ligands,
The composite material wherein the metal ion includes zinc and the organic ligand includes oxalic acid and 1,2,4-triazole.

According to the present disclosure, a fluorocarbon having one carbon number can be separated.

FIG. 1 shows the adsorption isotherm of Example 1. FIG. 2 shows the adsorption isotherm of Example 1. FIG. 3 shows adsorption isotherms of Comparative Examples 2 and 3. FIG. 4 shows the adsorption breakthrough curve of Example 1. FIG. 5 shows the adsorption breakthrough curve of Example 2. FIG. 6 shows adsorption isotherms in repeated adsorption and desorption in Example 1. FIG. 7 shows the adsorption isotherm of Example 1 after storage at high temperature and high humidity.

The separation method of the present disclosure includes:
Separating a fluorocarbon having a carbon number of 1 from a mixture containing a fluorocarbon having a carbon number of 1 and a fluorocarbon having a carbon number of 2 or more,
The separation of the 1-carbon fluorocarbon is carried out by bringing the mixture into contact with an adsorbent.

According to the separation method of the present disclosure, the fluorocarbon having 1 carbon number can be separated from the mixture by adsorbing the fluorocarbon having 1 carbon number on the adsorbent. In one embodiment, the mixture is contacted with the adsorbent in gaseous form.

(blend)
The mixture contains a fluorocarbon having 1 carbon atom.

The molecular diameter of the above-mentioned fluorocarbon having 1 carbon number is, for example, 0.30 nm or more and 0.430 nm or less, preferably 0.320 nm or more and 0.420 nm or less. In one embodiment, the molecular diameter of the fluorocarbon having 1 carbon number is, for example, 0.300 nm or more, preferably 0.320 nm or more, and, for example, 0.430 nm or less, preferably 0.420 nm or less.

The above molecular diameter is a value calculated by the following formula.
d=(ma/(3×21/2ηπ))1/2…(x1)
However, in formula (x1), d represents the molecular diameter, m represents the mass of one molecule, a represents the molecular velocity, and η represents the viscosity coefficient.
a is calculated by the following formula.
a=(γRT/M)1/2...(x2)
Here, γ is the specific heat ratio, which is approximated as 1.333. Further, R is a gas constant, T is an absolute temperature, and M is a molar molecular mass.
Further, η may be measured by a capillary method.

The boiling point of the fluorocarbon having 1 carbon atom may be, for example, -80°C or more and -20°C or less, and further may be -60°C or more and -30°C or less. In one embodiment, the C1 fluorocarbon is present as a gas in the mixture.

Examples of the above-mentioned fluorocarbon having 1 carbon number include hydrochlorofluorocarbon and hydrofluorocarbon. Examples of the hydrochlorofluorocarbon include chlorodifluoromethane, and examples of the hydrofluorocarbon include difluoromethane. Note that in the present disclosure, a fluorocarbon having 1 carbon number is also referred to as an adsorbate.

The above-mentioned fluorocarbon having 1 carbon number may contain one or more kinds of compounds. When the fluorocarbon having 1 carbon number contains two or more kinds of compounds, each compound preferably has a molecular diameter and a boiling point within the above ranges.

The content of the C1 fluorocarbon in the mixture may be, for example, 0.1 mol% or more and 50 mol% or less, and further 0.5 mol% or more and 20 mol% or less, in the entire mixture.

The above mixture contains a fluorocarbon having 2 carbon atoms.

The content of the fluorocarbon having 2 to 3 carbon atoms in the fluorocarbon having 2 or more carbon atoms may be, for example, 50 mol% or more and 100 mol% or less, and 80 mol% or more and 100 mol% or less.

The molecular diameter of the fluorocarbon having 2 or more carbon atoms is, for example, more than 0.430 nm, may be 0.404 nm or more and 2.00 nm or less, and may be 0.440 nm or more and 1.00 nm or less. In one embodiment, the molecular diameter of the fluorocarbon having 2 or more carbon atoms is, for example, more than 0.430 nm, preferably 0.440 nm or more, and is, for example, 2.00 nm or less, preferably 1.00 nm or less.

The boiling point of the fluorocarbon having 2 or more carbon atoms may be, for example, from -80°C to -20°C, further from -60°C to -30°C, especially from -50°C to -30°C. It's fine. In one embodiment, the fluorocarbon having two or more carbon atoms is present as a gas in the mixture.

Further, the difference between the boiling point of the fluorocarbon having 1 carbon number and the boiling point of the fluorocarbon having 2 or more carbon atoms may be, for example, 0°C or more and 20°C or less, and further may be 0°C or more and 10°C or less. According to the separation method of the present disclosure, even if the boiling points of the fluorocarbon having 1 carbon number and the fluorocarbon having 2 or more carbon atoms are close to each other, the fluorocarbon having 1 carbon number can be separated.

The fluorocarbon having 2 or more carbon atoms may be a saturated fluorocarbon or an unsaturated fluorocarbon, and is preferably a saturated fluorocarbon.

Examples of the fluorocarbon having 2 or more carbon atoms include hydrochlorofluorocarbon and hydrofluorocarbon. Examples of the hydrochlorofluorocarbon include hydrochlorofluorocarbons having 2 carbon atoms such as chlorotrifluoroethane. The above-mentioned hydrofluorocarbons include difluoroethane (e.g., 1,1-difluoroethane, 1,2-difluoroethane, especially 1,1-difluoroethane), trifluoroethane (e.g., 1,1,1-trifluoroethane, 1,1-difluoroethane), , 2-trifluoroethane, especially 1,1,1-trifluoroethane), tetrafluoroethane (e.g. 1,1,1,2-tetrafluoroethane, 1,1,2,2-tetrafluoroethane, In particular, hydrofluorocarbons having 2 carbon atoms such as 1,1,1,2-tetrafluoroethane) and pentafluoroethane; hydrofluorocarbons having 3 carbon atoms such as tetrafluoropropene and hexafluoropropene. The above-mentioned fluorocarbons having 2 or more carbon atoms may contain one type or two or more types.

In a preferred embodiment, the fluorocarbon having 2 or more carbon atoms may be, for example, a fluorocarbon having 2 to 5 carbon atoms, preferably a fluorocarbon having 2 to 3 carbon atoms.

The above-mentioned fluorocarbon having 2 or more carbon atoms may contain one or more kinds of compounds. When the fluorocarbon having two or more carbon atoms contains two or more types of compounds, it is preferable that the molecular diameter and boiling point of each compound are within the above ranges.

The content of the fluorocarbon having 1 carbon number and the fluorocarbon having 2 or more carbon atoms in the above mixture is preferably 90 mol% or more and 100 mol% or less, more preferably 95 mol% or more and 100 mol% or less, based on the entire mixture. .

The above mixture may contain other compounds in addition to the fluorocarbon having 1 carbon number and the fluorocarbon having 2 or more carbon atoms. The boiling point of such other compounds may be, for example, -100°C or lower, or -150°C or lower. In one embodiment, such other compounds are included in the mixture as a gas.

Examples of the other compounds include nitrogen, oxygen, carbon dioxide, water, and the like.

(adsorbent)
The above-mentioned adsorbent can adsorb fluorocarbon having 1 carbon number. Typically, the adsorbent adsorbs fluorocarbons having 1 carbon number and does not adsorb fluorocarbons having 2 or more carbon atoms. Therefore, by bringing a mixture containing a fluorocarbon having 1 carbon number and a fluorocarbon having 2 or more carbon atoms into contact with an adsorbent, the fluorocarbon having 1 carbon number can be separated from the mixture.

The adsorbent preferably includes a porous body having pores as an adsorbent. By adsorbing the fluorocarbon having 1 carbon into such pores, the fluorocarbon having 1 carbon can be separated from the above mixture.

Preferably, the effective pore diameter of the porous body is smaller than the molecular diameter of the fluorocarbon having 2 carbon atoms. When the effective pore diameter is smaller than the molecular diameter of the fluorocarbon having 2 carbon atoms, the fluorocarbon having 1 carbon number can be separated more reliably.

Here, the effective pore diameter is the pore diameter of a porous body determined from the degree of adsorption and molecular diameter of the adsorbate when the porous body and adsorbate are brought into contact with each other. - It can be determined by converting the relative pressure of the nitrogen adsorption isotherm into the effective pore diameter using the Kawazoe method. The conversion formula is J. Chem. Eng. Jpn. , 1983, 16, 6, 470-475 may be used, and the parameter values in the conversion equation may be values based on the combination of carbon and nitrogen.

The effective pore diameter of the porous body is, for example, 0.30 nm or more and 0.46 nm or less, preferably 0.32 nm or more and 0.44 nm or less. In one aspect, the effective pore diameter of the porous body is, for example, 0.30 nm or more, preferably 0.32 nm or more, and is, for example, 0.46 nm or less, preferably 0.44 nm or less.

The specific surface area of the porous body may be, for example, 40 m ² /g or more, preferably 100 m ² /g or more, more preferably 300 m ² /g or more, and may be, for example, 2,000 m ² /g or less, It may be 1,000 m ² /g or less. The specific surface area of the porous body is calculated from the nitrogen gas adsorption isotherm using the BET method.

The equilibrium adsorption amount of fluorocarbon having 1 carbon in the porous body may be, for example, 1 g/10 g or more and 100 g/10 g or less when measured at a temperature of 303 K and a pressure of 0.4 Pa to 1 MPa. good.

The porous body may be in the form of a powder (particulate), film, granule, molded body (pellet shape, etc.), preferably a molded body, and more preferably a pellet shape. Pellets may be cylindrical or spherical. In the case of a cylindrical shape, the radius of the cylinder is preferably 1.6 mm or more and 6 mm or less, and the thickness of the cylinder is preferably 2 mm or more and 6 mm or less. In the case of a spherical shape, including a shape that is not a perfect sphere, the radius of the sphere is preferably 4 mm or more and 12 mm or less.

The porous body preferably contains at least one member selected from the group consisting of zeolite, activated carbon, silica gel, and metal-organic framework (PCP: Porous Coordination Polymer, or MOF: Metal-Organic Framework). includes metal-organic frameworks.

Preferably, the metal-organic framework contains a metal ion and one or more organic ligands. Typically, an organic ligand contains two or more groups in one molecule that can coordinate to a metal ion, and the organic ligand has high regularity by coordinating with the metal ion. A three-dimensionally continuous structure (for example, a network structure) is formed, and pores are formed between the metal ion and the organic ligand. In such a three-dimensional structure, by combining the types of metal ions and organic ligands, the effective pore diameter and flexibility of the metal-organic structure and the interaction between the metal-organic structure and the adsorbate can be controlled.
In addition, the metal-organic structure does not reduce its adsorption amount (maximum adsorption amount) even after repeated adsorption and desorption of adsorbate, and has high repeat durability. Furthermore, the metal-organic structure is not easily affected by temperature (heat) and humidity, and even when stored for a long time under high temperature and high humidity, the amount of adsorption does not decrease, and it has high high temperature and high humidity durability.

The above-mentioned metal ions are, for example, metal ions selected from the group consisting of Group Ia, Group IIa, Group IIIa, Groups IVa to VIII, and Groups Ib to VIb, although they are not particularly limited. Such metals are preferably Mg, Ca, Sr, Ba, Sc, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Ro, Os, Co, Rh. , Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Hg, Al, Ga, In, TI, Si, Ge, Sn, Pb, As, Sb, Bi, La, Ce, Pr, Nd , Pm, Sm, En, Gd, Tb, Dy, Ho, Er, Tm, and Yb.

Specifically, such metal ions include Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ , Sc ³⁺ , Y ³⁺ , Ln ³⁺ , Ti 4+ , Zr ⁴⁺ , Hf ⁴⁺ , V ⁴⁺ , V ³⁺ , V ^{2+ ,} Nb ³⁺ , Ta ³⁺ , Cr ³⁺ , Mo ³⁺ , W ³⁺ , Mn ³⁺ , Mn ²⁺ , Re ³⁺ , Re ²⁺ , Fe ³⁺ , Fe ²⁺ , Ru ³⁺ , Ru ²⁺ , Os ³⁺ , Os ²⁺ , Co ³⁺ , Co ²⁺ , Rh ²⁺ , Rh ⁺ , Ir ²⁺ , Ir ⁺ , Ni ²⁺ , Ni ⁺ , Pd ²⁺ , Pd ⁺ , Pt ^{2+ , Pt + , Cu 2+ , Cu} + , Ag ⁺ , Au ^{+ ,} Zn ²⁺ , Cd ²⁺ , Hg ²⁺ , Al ³⁺ , Ga ³⁺ , ln ³⁺ , TI ³⁺ , Si ⁴⁺ , Si 2+ , Ge ⁴⁺ , Ge ²⁺ , Sn ⁴⁺ , Sn ²⁺ , Pb ⁴⁺ , ^{Pb 2+ ,} As ⁵⁺ , As ³⁺ , As ⁺ , Sb ⁵⁺ , Sb ³⁺ , Sb ⁺ , Bi ⁵⁺ , Bi ³⁺ , Bi ⁺ , La ³⁺ , Ce ³⁺ , Pr ³⁺ , Nd ³⁺ , Pm ³⁺ , Sm ³⁺ , En ³⁺ , Gd ³⁺ , Tb ³⁺ , Dy ³⁺ , Ho ³⁺ , Er ³⁺ , It can be Tm ³⁺ or Yb ³⁺ .

The number of the above-mentioned metal ions may be one type or two or more types. Preferably, the number of metal ions is one.

In a preferred embodiment, the metal ion is a Zn ion, preferably Zn ²⁺ .

The organic ligand is not particularly limited as long as it contains two or more groups in one molecule that can coordinately bond to a metal ion. The coordinate bond is formed by, for example, a functional group that can form a coordinate bond with a metal ion.

Examples of the functional groups capable of forming the coordinate bond include -COOH, -CS ₂ H, -NO ₂ , -B(OH) ₂ , -SO ₃ H, -Si(OH) ₃ , -Ge (OH) ₃ , -Sn(OH) ₃ , -Si(SH) ₄ , -Ge(SH) ₄ , -Sn(SH) ₃ , -PO ₃ H, -AsO ₃ H, -AsO ₄ H, -P (SH) ₃ , -As(SH) ₃ , -CH(RSH) ₂ , -C(RSH) ₃ , -CH(RNH ₂ ) ₂ , -C(RNH ₂ ) ₃ , -CH(ROH) ₂ , - Examples include C(ROH) ₃ , -CH(RCN) ₃ , and -C(RCN) ₃ . In the above formula, R is a single bond or an alkylene group having 1 to 5 carbon atoms (for example, methylene, ethylene, n-propylene, i-propylene, n-butylene, i-butylene, tert-butylene or n-pentylene group) , a divalent aromatic group having 6 to 14 carbon atoms (for example, phenylene), or a combination of the above alkylene group and an aromatic group (for example, -phenylene-alkylene-phenylene-). Further, the functional group capable of forming the coordinate bond may be a heteroatom contained in a heterocycle (for example, N, O, S, B, P, Si, Al), and preferably a heteroatom contained in a heterocycle. It may also be a nitrogen atom contained therein.

In a preferred embodiment, the functional group capable of forming the coordinate bond may be -COOH, a nitrogen atom included in a heterocycle, or the like.

The organic ligand preferably has the functional group so as to be bidentate or more. In such an organic ligand, the parts other than the functional group are not limited as long as the organic ligand can form a coordinate bond with a metal ion.

In one embodiment, the organic ligand is derived from a saturated or unsaturated aliphatic or aromatic compound. Moreover, the above-mentioned ligand may be derived from a compound in which such an aliphatic compound and an aromatic compound are bonded (hereinafter also referred to as "aliphatic aromatic compound").

The aliphatic portion of the aliphatic compound or aliphatic aromatic compound may be linear, branched, or cyclic. When the aliphatic moiety is cyclic, it may have multiple rings. The aliphatic moiety of the aliphatic compound or aliphatic aromatic compound preferably has 1 to 15 carbon atoms, more preferably 1 to 10 carbon atoms, such as 1, 2, 3, 4, 5 , 6, 7, 8, 9 or 10 carbon atoms. In a preferred embodiment, the aliphatic moiety is derived from methane, adamantane, acetylene, ethylene or butadiene.

The aromatic moiety of the aromatic compound or araliphatic compound may have one or more rings, for example 2, 3, 4 or 5 rings. These rings may be fused or unfused. The aromatic moiety of the aromatic compound or aliphatic aromatic compound preferably has 1, 2 or 3 rings, more preferably 1 or 2 rings. Each ring of the above compounds may also have at least one heteroatom in the ring, such as N, O, S, B, P, Si, Al, preferably N, O or S. The aromatic compound or the aromatic moiety of the aromatic aliphatic compound preferably contains one or two rings each having 6 carbon atoms. When there are two aromatic moieties, the two rings may or may not be fused. In preferred embodiments, such aromatic moieties are derived from benzene, naphthalene, biphenyl, bipyridyl or pyridyl.

In one embodiment, the organic ligand is derived from dicarboxylic, tricarboxylic or tetracarboxylic acids.

Examples of the dicarboxylic acids include oxalic acid, succinic acid, tartaric acid, maleic acid, 1,4-butanedicarboxylic acid, 1,4-butenedicarboxylic acid, 4-oxopyran-2,6-dicarboxylic acid, 1,6- Hexanedicarboxylic acid, decanedicarboxylic acid, 1,8-heptadecanedicarboxylic acid, 1,9-heptadecanedicarboxylic acid, heptadecanedicarboxylic acid, acetylenedicarboxylic acid, 1,2-benzenedicarboxylic acid, 1,3-benzenedicarboxylic acid , 2,3-pyridinedicarboxylic acid, pyridine-2,3-dicarboxylic acid, 1,3-butadiene-1,4-dicarboxylic acid, 1,4-benzenedicarboxylic acid, p-benzenedicarboxylic acid, imidazole-2,4 -dicarboxylic acid, 2-methylquinoline-3,4-dicarboxylic acid, quinoline-2,4-dicarboxylic acid, quinoxaline-2,3-dicarboxylic acid, 6-chloroquinoxaline-2,3-dicarboxylic acid, 4,4' -diaminophenylmethane-3,3'-dicarboxylic acid, quinoline-3,4-dicarboxylic acid, 7-chloro-4-hydroxyquinoline-2,8-dicarboxylic acid, diimidodicarboxylic acid, pyridine-2,6-dicarboxylic acid , 2-methylimidazole-4,5-dicarboxylic acid, thiophene-3,4-dicarboxylic acid, 2-isopropylimidazole-4,5-dicarboxylic acid, tetrahydropyran-4,4-dicarboxylic acid, perylene-3,9 -dicarboxylic acid, perylene dicarboxylic acid, Pluriol E200-dicarboxylic acid, 3,6-dioxaoctane dicarboxylic acid, 3,5-cyclohexadiene-1,2-dicarboxylic acid, octane dicarboxylic acid, pentane-3,3-dicarboxylic acid , 4,4'-diamino-1,1'-biphenyl-3,3'-dicarboxylic acid, 4,4'-diaminobiphenyl-3,3'-dicarboxylic acid, benzidine-3,3'-dicarboxylic acid, 1 , 4-bis(phenylamino)benzene-2,5-dicarboxylic acid, 1,1'-binaphthyldicarboxylic acid, 7-chloro-8-methylquinoline-2,3-dicarboxylic acid, 1-anilino-anthraquinone-2, 4'-dicarboxylic acid, polytetrahydrofuran 250-dicarboxylic acid, 1,4-bis(carboxymethyl)piperazine-2,3-dicarboxylic acid, 7-chloroquinoline-3,8-dicarboxylic acid, 1-(4-carboxylic) Phenyl-3-(4-chloro)phenylpyrazoline-4,5-dicarboxylic acid, 1,4,5,6,7,7-hexachloro-5-norbornene-2,3-dicarboxylic acid, phenylindanedicarboxylic acid, 1,3-dibenzyl-2-oxoimidazolidine-4,5-dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, naphthalene-1,8-dicarboxylic acid, 2-benzoylbenzene-1,3-dicarboxylic acid, 1, 3-dibenzyl-2-oxoimidazolidene-4,5-cis-dicarboxylic acid, 2,2'-biquinoline-4,4'-dicarboxylic acid, pyridine-3,4-dicarboxylic acid, 3,6,9-trio Xaoundecane dicarboxylic acid, hydroxybenzophenone dicarboxylic acid, Pluriol E300-dicarboxylic acid, Pluriol E400-dicarboxylic acid, Pluriol E600-dicarboxylic acid, pyrazole-3,4-dicarboxylic acid, 2,3-pyrazinedicarboxylic acid, 5,6-dimethyl -2,3-pyrazine dicarboxylic acid, 4,4'-diamino(diphenyl ether) diimide dicarboxylic acid, 4,4'-diaminodiphenylmethane diimide dicarboxylic acid, 4,4'-diamino(diphenylsulfone) diimide dicarboxylic acid, 1,4 -Naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 1,3-adamantanedicarboxylic acid, 1,8-naphthalene dicarboxylic acid, 2,3-naphthalene dicarboxylic acid, 8-methoxy-2,3-naphthalene dicarboxylic acid, 8 -Nitro-2,3-naphthalene dicarboxylic acid, 8-sulfo-2,3-naphthalene dicarboxylic acid, anthracene-2,3-dicarboxylic acid, 2',3'-diphenyl-p-terphenyl-4,4"- Dicarboxylic acid, (diphenyl ether)-4,4'-dicarboxylic acid, imidazole-4,5-dicarboxylic acid, 4(1H)-okiothiochromene-2,8-dicarboxylic acid, 5-tert-butyl-1,3 -Benzenedicarboxylic acid, 7,8-quinolinedicarboxylic acid, 4,5-imidazoledicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, hexatriacontanedicarboxylic acid, tetradedocanedicarboxylic acid, 1,7-heptanedicarboxylic acid acid, 5-hydroxy-1,3-benzenedicarboxylic acid, 2,5-dihydroxy-1,4-dicarboxylic acid, pyrazine-2,3-dicarboxylic acid, furan-2,5-dicarboxylic acid, 1-nonene-6 , 9-dicarboxylic acid, eicosene dicarboxylic acid, 4,4'-dihydroxydiphenylmethane-3,3'-dicarboxylic acid, 1-amino-4-methyl-9,10-dioxo-9,10-dihydroanthracene-2, 3-dicarboxylic acid, 2,5-pyridinedicarboxylic acid, cyclohexene-2,3-dicarboxylic acid, 2,9-dichlorofluorobin-4,11-dicarboxylic acid, 7-chloro-3-methylquinoline-6,8- Dicarboxylic acid, 2,4-dichlorobenzophenone-2',5'-dicarboxylic acid, 1,3-benzenedicarboxylic acid, 2,6-pyridinedicarboxylic acid, 1-methylpyrrole-3,4-dicarboxylic acid, 1-benzyl -1H-pyrrole-3,4-dicarboxylic acid, anthraquinone-1,5-dicarboxylic acid, 3,5-pyrazoledicarboxylic acid, 2-nitrobenzene-1,4-dicarboxylic acid, heptane-1,7-dicarboxylic acid, cyclobutane -1,1-dicarboxylic acid, 1,14-tetradedokanedicarboxylic acid, 5,6-dehydronorbornane-2,3-dicarboxylic acid, 5-ethyl-2,3-pyridinedicarboxylic acid, and camphordicarboxylic acid. It will be done.

Examples of the above tricarboxylic acids include 2-hydroxy-1,2,3-propanetricarboxylic acid, 7-chloro-2,3,8-quinolinetricarboxylic acid, 1,2,3-,1,2,4-benzene Tricarboxylic acid, 1,2,4-butanetricarboxylic acid, 2-phosphono-1,2,4-butanetricarboxylic acid, 1,3,5-benzenetricarboxylic acid, 4,4',4''-(1,3, 5-benzentriyl) trisbenzoic acid, 1-hydroxy-1,2,3-propanetricarboxylic acid, 4,5-dihydro-4,5-dioxo-1H-pyrrolo[2,3-F]quinoline-2, 7,9-tricarboxylic acid, 5-acetyl-3-amino-6-methylbenzene-1,2,4-tricarboxylic acid, 3-amino-5-benzoyl-6-methylbenzene-1,2,4-tricarboxylic acid , 1,2,3-propanetricarboxylic acid, and aurinetricarboxylic acid.

The above-mentioned tetracarboxylic acid includes 1,1-dioxidoperillo[1,12-BCD]thiophene-3,4,9,10-tetracarboxylic acid, perylene-3,4,9,10-tetracarboxylic acid, or (perylene- Perylenetetracarboxylic acids such as 1,12-sulfone)-3,4,9,10-tetracarboxylic acid, 1,2,3,4-butanetetracarboxylic acid or meso-1,2,3,4-butanetetracarboxylic acid Carboxylic acids such as butanetetracarboxylic acid, decane-2,4,6,8-tetracarboxylic acid, 1,4,7,10,13,16-hexaoxacyclooctadecane-2,3,11,13-tetracarboxylic acid acid, 1,2,4,5-benzenetetracarboxylic acid, 1,2,11,12-dodecanetetracarboxylic acid, 1,2,5,6-hexanetetracarboxylic acid, 1,2,7,8-octane Tetracarboxylic acid, 1,4,5,8-naphthalenetetracarboxylic acid, 1,2,9,10-decanetetracarboxylic acid, benzophenonetetracarboxylic acid, 3,3',4,4'-benzophenonetetracarboxylic acid, Examples include cyclopentanetetracarboxylic acids such as tetrahydrofurantetracarboxylic acid and cyclopentane-1,2,3,4-tetracarboxylic acid.

In one embodiment, the organic ligand is derived from a heterocycle capable of forming coordination bonds through ring heteroatoms. Such heterocycles include the following heterocycles. The heterocycle may be unsubstituted or substituted.

In one embodiment, the organic ligand is derived from an azole, such as a diazole, a triazole, preferably a triazole.

In a preferred embodiment, the organic ligand includes an organic ligand derived from dicarboxylic acid and an organic ligand derived from azole, preferably an organic ligand derived from oxalic acid and 1,2,4 - Contains organic ligands derived from triazoles.

The number of the above-mentioned organic ligands may be one, or two or more.

In addition, in this disclosure, "derived from a compound" includes not only the compound itself but also a partially protonated form or a completely protonated form of the compound. It will be done.

The above-mentioned metal-organic framework can be produced by bringing a metal ion into contact with an organic ligand.
Such contact between metal ions and organic ligands may be carried out in the presence of a solvent. The above solvents include water, ethanol, dimethylformamide, toluene, methanol, chlorobenzene, diethylformamide, dimethyl sulfoxide, water, hydrogen peroxide, methylamine, sodium hydroxide solution, N-methylpyrrolidone ether, acetonitrile, benzyl chloride, triethylamine. or ethylene glycol, or a mixture thereof.

The above-mentioned contact between the metal ion and the organic ligand may be carried out under pressure or under normal pressure. Further, the temperature at which such contact is carried out may be, for example, 10 to 200°C, or 10 to 150°C. Further, when carrying out such contact, stirring may be performed.

When the metal ion contains Zn ²⁺ and the organic ligand contains oxalic acid and 1,2,4-triazole, a mixture of water and ethanol is used as a solvent during contact between the metal ion and the organic ligand. The metal-organic structure can be produced by stirring under normal pressure at a temperature of, for example, 10 to 30°C, and the productivity is good.

The content of the porous material in the adsorbent is, for example, 50% by mass or more and 100% by mass or less, preferably 70% by mass or more and 100% by mass or less, and more preferably 90% by mass or more and 100% by mass or less.

The adsorbent may contain a resin in addition to the above-mentioned porous body. Examples of such resins include acrylic resins, polyurethane resins, polyolefin resins, polyester resins, polyamide resins, vinyl chloride resins, styrene resins, vinyl ether resins, polyvinyl alcohol resins, polycarbonate resins, and polysulfone resins.

The above adsorbents include emulsifiers, antifoaming agents, surfactants, leveling agents, thickeners, viscoelastic modifiers, antifoaming agents, wetting agents, dispersants, preservatives, plasticizers, penetrants, fragrances, and bactericidal agents. , acaricides, fungicides, ultraviolet absorbers, antioxidants, antistatic agents, flame retardants, dyes, pigments, and other additives. Further, the adsorbent may be in the form of powder, granules, flakes, or pellets.

(Contact between mixture and adsorbent)
By bringing the mixture into contact with the adsorbent, the 1-carbon fluorocarbon contained in the mixture is adsorbed by the adsorbent, and the 1-carbon fluorocarbon can be separated from the mixture. In one embodiment, when contacting such a mixture with an adsorbent, the mixture is preferably contacted as a gas.

Contacting the mixture with the adsorbent may be carried out, for example, by a batch method or a column method. The batch method is a method in which the adsorbent and the mixture are placed in a sealable container and allowed to stand for a certain period of time under conditions of a predetermined temperature and a predetermined pressure, thereby bringing the mixture and the adsorbent into contact with each other. Further, the column method is a method in which a container (column) is filled with an adsorbent and the mixture is caused to come into contact with the adsorbent by flowing the mixture into the container (column).

The temperature during the above-mentioned contact may be, for example, 10°C or more and 40°C or less, and further 15°C or more and 35°C or less. Moreover, the pressure (gauge pressure) at the time of the above-mentioned contact may be 0.2 MPaG or more and 2 MPaG or less, and may be 0.4 MPaG or more and 1.5 MPaG or less. When the pressure at the time of contact is within the above range, the adsorbate is easily adsorbed by the adsorbent, the separation efficiency can be improved, and the pore structure of the adsorbent can be maintained.

When the above-mentioned contact is carried out by a column method, the flow rate of the above-mentioned mixture may be 50 mL/min or more and 1,000 mL/min or less, and may be 100 mL/min or more and 500 mL/min or less.

The 1-carbon fluorocarbon adsorbed on the adsorbent can be desorbed from the adsorbent by reducing the pressure, increasing the temperature, or the like. Thereby, the adsorbent can be regenerated and the fluorocarbon having one carbon number can be recovered.

(purification)
The separation method of the present disclosure may further include purifying the separated 1-carbon fluorocarbon. Thereby, it is possible to reuse the fluorocarbon having one carbon number.

In one embodiment, the purification can be performed by distillation or rectification. Such distillation may be carried out using commonly used distillation columns, such as packed columns or tray columns. The purified product is distilled out as a distillate from the top of the distillation column, and the remainder is distilled out as a bottom product from the bottom of the distillation column. The number of theoretical plates in the distillation column may be, for example, 1 to 100 plates. The pressure (gauge pressure) during distillation or rectification may be 0 MPaG or more and 5 MPaG or less. Further, the temperature at the top of the distillation column may be, for example, -60°C or more and 100°C or less, and the temperature at the bottom of the distillation column may be, for example, 50°C or more and 200°C or less. An extraction solvent may be present during distillation.

Rectification can be carried out by performing an operation of distilling the above-mentioned distillate again (an operation of distilling the distillate twice or more).

(composite material)
A composite material including an adsorbent and a fluorocarbon having 1 carbon number is also included within the technical scope of the present disclosure. In such a composite material, any of the adsorbents described above can be used, and it is preferable that the adsorbent contains a metal-organic framework. Preferably, the metal ion in the metal-organic framework includes zinc, and the organic ligand preferably includes oxalic acid and 1,2,4-triazole.

In the composite material, the content of the fluorocarbon having 1 carbon atom is, for example, 1 part by mass or more and 100 parts by mass or less, preferably 10 parts by mass or more and 50 parts by mass or less, based on 100 parts by mass of the adsorbent.

The present disclosure will be explained in more detail with reference to the following examples, but the present disclosure is not limited thereto.

Examples 1 to 3, Comparative Examples 1 to 3
As adsorbents, metal-organic structure 1 (CALF-20, manufactured by Atomis), metal-organic structure 2 (NEJSAY, manufactured by Atomis), and metal-organic structure 3 (MIL-120, manufactured by Atomis) shown in Tables 1 and 3 were used. (manufactured by Union Showa), metal organic framework 4 (ZIF-8, manufactured by Atomis), zeolite 1 (MS-4A, manufactured by Union Showa), and zeolite 2 (MS-13X, manufactured by Union Showa) were used. As a pretreatment for the adsorbent used, vacuum treatment was performed at 110° C. for 12 hours.

(Specific surface area measurement)
The specific surface areas of pretreated metal-organic structures (PCP) 1 to 3 were measured. The specific surface area was measured using an automatic specific surface area/pore distribution measuring device "BELSORP-mini II" manufactured by Microtrac Bell Co., Ltd., and calculated by the BET method. The results are shown in Table 1.

(Adsorption amount measurement)
The amount of adsorption of chlorodifluoromethane (R22) and pentafluoroethane (R125) was measured at 303 K for the metal organic frameworks (PCP) 1 to 3 of Examples 1 to 3 that were pretreated as described above. Ta. As the adsorption amount measuring device, two types of devices shown in the table below were used depending on the measurement pressure range.
In addition, adsorption amounts were measured for pretreated metal-organic structures (PCP) 1 to 4 and zeolites 1 and 2, and adsorption isotherms were obtained. The adsorption amount at the time of obtaining the adsorption isotherm was measured using an automatic specific surface area/pore distribution measuring device "BELSORP-max" or "BELSORP-HP" manufactured by Microtrac Bell Co., Ltd.

FIG. 1 shows chlorodifluoromethane (R22), difluoromethane (R32), pentafluoroethane (R125), 1,1 measured at 303 K for the metal-organic framework (PCP) 1 (powder) of Example 1. , 1-trifluoroethane (R143a). From FIG. 1, it can be seen that R22 and R32, which are fluorocarbons having one carbon number, were adsorbed to the metal-organic structure 1, while R125 and R143a, which are fluorocarbons having two carbon atoms, were hardly adsorbed.

FIG. 2 shows adsorption isotherms of R22 measured at 283 K, 293 K, 303 K, and 313 K for the metal-organic framework (PCP) 1 (powder) of Example 1. From FIG. 2, it can be seen that the amount of adsorption at 283K is the largest, and there is almost no difference in the amount of adsorption between 293 and 313K. "BELSORP-max" was used for the measurement.

Similarly, for the metal organic frameworks (PCP) 2 and 3 of Examples 2 and 3, the metal organic framework (PCP) 4 of Comparative Example 1, and the zeolites 1 and 2 (powdered) of Comparative Examples 2 and 3, Adsorption isotherms of R22 and R125 were obtained, and the amounts of adsorption that reached equilibrium are summarized in Table 3. "BELSORP-HP" was used for the measurement.

FIG. 3 shows adsorption isotherms of R22 and R125 measured at 303 K for MS-4A of Comparative Example 2 and MS-13X of Comparative Example 3 as adsorbents (porous bodies). "BELSORP-HP" was used for the measurement.

(Adsorption breakthrough measurement of mixed gas)
In Figure 4, a mixed gas of R125/R22 = 98 mol%/2 mol% was passed through an adsorption tower filled with CALF-20 (pellet form) of Example 1 at a total pressure of 0.6 MPaG, a temperature of 298 K, and a flow rate of 250 mL/min. An adsorption breakthrough curve obtained by measuring the R22 and R125 concentrations at the outlet of the adsorption tower is shown. The adsorption amount of R22 obtained from the adsorption breakthrough curve was 0.223 g/g, which was approximately the same value as the equilibrium adsorption amount of the adsorption isotherm. The molecular diameter of R125 was 0.446 nm, and the molecular diameter of R22 was 0.418 nm.

In Figure 5, a mixed gas of R125/R32 = 92 mol%/8 mol% was passed through an adsorption tower filled with CALF-20 (pellet form) of Example 1 at a total pressure of 0.6 MPaG, a temperature of 298 K, and a flow rate of 320 mL/min. An adsorption breakthrough curve obtained by measuring the R32 and R125 concentrations at the outlet of the adsorption tower is shown. The amount of R32 adsorbed obtained from the adsorption breakthrough curve was 0.129 g/g, which was approximately the same value as the equilibrium adsorption amount of the adsorption isotherm. The molecular diameter of R32 was 0.363 nm.

(Repeated adsorption/desorption durability test of metal-organic structures)
FIG. 6 shows an adsorption isotherm obtained by repeating adsorption and desorption of chlorodifluoromethane (R22) on the metal organic framework (PCP) 1 of Example 1 at a temperature of 303 K and measuring the amount of adsorption. "BELSORP-HP" was used for the measurement. There was no decrease in the maximum adsorption amount even after 300 repeated tests, and it can be said that it has high durability in repeated adsorption and desorption.

(High temperature and high humidity durability test)
FIG. 7 shows the metal-organic structure (PCP) 1 of Example 1 and the metal-organic structure (PCP) 1 of Example 1 for 14 days and 28 days under conditions of a temperature of 85° C. and a humidity of 95% RH. The adsorption isotherms obtained by measuring the adsorption amount of chlorodifluoromethane (R22) at 303K for each sample stored for 42 and 56 days are shown. "BELSORP-HP" was used for adsorption isotherm measurement. In the sample stored under high temperature and high humidity, the decrease in adsorption amount was suppressed compared to the case where the sample was not stored under high temperature and high humidity, and it can be said that the high temperature and high humidity durability is good.

Claims (11)

Separating a fluorocarbon having a carbon number of 1 from a mixture containing a fluorocarbon having a carbon number of 1 and a fluorocarbon having a carbon number of 2 or more,
A method for separating fluorocarbons, wherein the separation of the fluorocarbon having 1 carbon number is carried out by bringing the mixture into contact with an adsorbent. The separation method according to claim 1, wherein the fluorocarbon having 1 carbon number is at least one selected from the group consisting of difluoromethane and difluorochloromethane. The separation method according to claim 1, wherein the fluorocarbon having 2 or more carbon atoms includes a fluorocarbon having 2 to 3 carbon atoms. The separation method according to claim 1, wherein the adsorbent includes a porous body, and the porous body has an effective pore diameter of 0.46 nm or less. The separation method according to claim 4, wherein the porous body includes a metal organic framework. The metal-organic framework contains a metal ion and one or more organic ligands,
6. The separation method according to claim 5, wherein the organic ligand contains two or more groups in one molecule that can coordinately bond to the metal ion. 7. The separation method according to claim 6, wherein the metal ion includes zinc, and the organic ligand includes oxalic acid and 1,2,4-triazole. The separation method according to claim 4, wherein the adsorbent further contains a resin. The separation method according to any one of claims 1 to 8, wherein the adsorbent is in the form of powder, granules, flakes, or pellets. The separation method according to any one of claims 1 to 9, further comprising refining the separated 1-carbon fluorocarbon. including a metal-organic framework and a fluorocarbon having 1 carbon number,
The metal-organic framework contains a metal ion and one or more organic ligands,
The composite material wherein the metal ion includes zinc and the organic ligand includes oxalic acid and 1,2,4-triazole.

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